IFNG and infection: Given that IL-10 can be produced by different cells in the innate and adaptive immune arms, and that some Th1 and Treg cell subsets can simultaneously produce IFN-γ and IL-10 during infection (e.g., Leishmania and Rickettsia) [44], [45], [46], it will be interesting to examine the roles of IL-10 during O. tsutsugamushi infection.